US4271124A - Non-dispersive infrared gas analyzer for testing gases containing water-vapor - Google Patents

Non-dispersive infrared gas analyzer for testing gases containing water-vapor Download PDF

Info

Publication number
US4271124A
US4271124A US06/014,432 US1443279A US4271124A US 4271124 A US4271124 A US 4271124A US 1443279 A US1443279 A US 1443279A US 4271124 A US4271124 A US 4271124A
Authority
US
United States
Prior art keywords
gas
infrared
chamber
infrared radiation
path
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US06/014,432
Inventor
Winfried Speeter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Application granted granted Critical
Publication of US4271124A publication Critical patent/US4271124A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/37—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using pneumatic detection
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T436/00—Chemistry: analytical and immunological testing
    • Y10T436/20—Oxygen containing
    • Y10T436/204998—Inorganic carbon compounds
    • Y10T436/205831—Carbon monoxide only

Definitions

  • This invention relates to systems for measuring the water vapor content of a gas mixture, and more particularly, to systems for suppressing the water vapor cross sensitivity in a non-dispersive infrared absorption gas analyzer.
  • Infrared absorption gas analyzers operate utilizing a physical property of gases in which the different atomic structures of different gases absorb corresponding spectral regions of infrared radiation. Such absorption of infrared energy by gas contained within a closed volume causes a measureable increase in its temperature and pressure.
  • concentrations of predetermined gaseous components within a gas mixture can be determined from temperature and pressure measurements.
  • a typical prior art system for obtaining the desired temperature and pressure measurements utilizes a source of infrared radiation which transmits electromagnetic energy in the infrared range through a measurement cell which contains a sample of the gas mixture which is to be examined, and a receiver chamber which contains a sample of the gas component, either in pure form or mixed with other gases, of the type which is desired to be measured.
  • the measurement cell and the receiver chamber which are each disposed in the path of the infrared energy, contain windows of a material which is transparent in the infrared spectral region, typically having wavelengths in the range between 2 and 10 microns, so as to permit the energy to propagate through the various gases.
  • the gas mixture contained in the measurement cell contains gaseous components which cause "cross sensitivities". Such cross sensitivities may be caused by water vapor contained in the measurement gas, which interferes with the measurement of other gaseous components. It is desirable to eliminate the interfering component by interposing a filter cell, which is commonly filled with a filter gas corresponding to the interfering component, and which is disposed in the radiation path so as to absorb the particular interfering spectral components from the radiation. Alternatively, in the case of water vapor, it may be desirable to measure the water vapor component by filling the receiver chamber with water vapor.
  • infrared radiation which passes through the gaseous mixture in the measurement cell would also propagate through the receiver chamber, affect the thermodynamic state of the water vapor in the receiver chamber, and such changes could be converted to electrical signals for measuring the water vapor content of the gaseous mixture in the measurement cell.
  • sulfur hexafluoride SF 6 as a gas for selectively filtering spectral components corresponding to water vapor, or as a reference gas in a receiver chamber for determining the water vapor component in a gas mixture to be measured.
  • sulfur hexafluoride can be used as a substitute for water vapor. It can be mixed with other gases in predetermined proportional quantities, so as to achieve a predeterminable partial pressure of sulfur hexafluoride in a filter gas. As indicated, such additional component gases may be of a type which do not absorb infrared radiation, such as nitrogen or argon, or may by of a type which absorb a predetermined interference component in the infrared spectrum, such as carbon dioxide.
  • the selective filtering effect of sulfur hexafluoride may be advantageously adjustable in response to its partial pressure in the gas mixture.
  • German Pat. reference No. 1 109 148 A known infrared gas analyzer system which may benefit from the use of this invention is shown in German Pat. reference No. 1 109 148.
  • two spectrally selective radiation receivers are provided, and are disposed behind one another in the path of an infrared energy beam.
  • the infrared radiation receivers are disposed on the other side of a measuring cell from a source of infrared radiation.
  • the receivers are in the form of radiation-permeable, gas-filled chambers, which are provided with means for converting variation in the pressure or temperature of the gas resulting from the absorption of the infrared energy into responsive electrical output signals.
  • the respective responsive output signals are combined in a difference circuit.
  • one of the radiation receivers is filled with sulfur hexafluoride, and the other radiation receiver is filled with the component gas to be measured.
  • the output signal of the radiation receiver filled with sulfur hexafluoride is weighted with a percentage factor and electrically combined in the difference circuit so as to tend to counteract the output signal of the other radiation receiver.
  • Such a differential combination of output signals compensates for water vapor cross sensitivity.
  • FIG. 1 depicts an infrared gas analyzer, partly in schematic form and partly in block and line representation, which operates in accordance with a single beam alternating light method;
  • FIG. 2 shows an infrared gas analyzer, partly in schematic form and partly in block and line representation, which operates in accordance with a double beam alternating light method
  • FIG. 3 shows an infrared gas analyzer system, partly in schematic form and partly in block and line representation, which utilizes a single alternating beam with a selective receiver
  • FIG. 4 shows an infrared gas analyzer, partly in schematic form and partly in block and line representation, utilizing a non-selective receiver and subtractive filtering.
  • FIG. 1 shows an infrared gas analyzer which operates in accordance with the known single-beam alternating-light method.
  • An infrared radiation source 1 is disposed within a reflector 2, so as to direct the infrared radiation along a path M.
  • a measuring cell 3, a filter cell 4 and a receiver chamber 5 are sequentially disposed along path M.
  • the end faces of measuring cell 3 and filter cell 4, and one end face of receiver chamber 5 are provided with windows 6 which are of an infrared transparent material, illustratively, calcium fluoride.
  • measurement cell 3 is filled with a measurement gas 7 which may be composed of a variety of gaseous components, including water vapor; measurement gas 7 being circulated through measuring cell 3 as shown by the directional arrows at the inlet and outlet of the measuring cell.
  • the particular component of the measuring gas mixture 7, which is to be determined quantitatively, is present in either a pure form or mixed with non-absorbing gases as reference gas 8 in receiver chamber 5.
  • a pressure transducer which, in this embodiment of the invention, is in the form of a diaphragm capacitor 9.
  • Diaphragm capacitor 9 is connected to a circuit 10 which is coupled at its output to an indicating device 11.
  • Indicating device 11 produces an indication which is responsive to the pressure of reference gas 8 in receiver chamber 5. Since diaphragm capacitor 9 and its associated circuitry will more easily process an alternating signal, the infrared energy propagating along path M is periodically interrupted by means of a rotating shutter 12.
  • a filter gas 13 which is contained in filter cell 4, is used to filter out the important absorption bands of water vapor in the wavelength region between 2 and 10 microns.
  • Filter gas 13 contains sulfur hexafluoride which may be alone, in combination with additional non-absorbing gases, or with other absorbing gases which are intended to filter out other spectral components.
  • FIG. 2 shows an infrared gas analyzer which operates in accordance with the two-beam alternating-light method.
  • An infrared radiation source 1 is disposed within a reflector 2, the output beam of which is divided by beam divider 14 into two parallel ray paths, M and V.
  • the propagation of infrared energy along paths M and V is alternatingly interrupted by rotating shutter 12.
  • Measuring cell 3 containing a measurement gas 7, and receiver chambers 17 and 5 are disposed sequentially along path M.
  • Reference cell 15 containing reference gas 16, and radiation receivers 17' and 5' are sequentially disposed along path V.
  • measurement gas 7 may consist of carbon monoxide, carbon dioxide and water vapor.
  • Reference gas 16 may be a non-absorbing gas such as nitrogen N 2 .
  • Receiver chambers 5 and 5' are each filled with carbon monoxide CO, which is the particular component of measurement gas 7 to be quantitatively determined. Receiver chambers 5 and 5' communicate with one another by means of a line, in which is disposed a thermal flow sensor 18. Thermal flow sensor 18 is connected to a measuring bridge circuit 19. Receiver chambers 17 and 17' are filled with a combination of sulfur hexafluoride SF 6 and carbon dioxide CO 2 so as to absorb the energies corresponding to the energy spectrum of interfering components carbon dioxide and water vapor H 2 O of the measurement gas 7. Pressure variations are detected by thermal flow sensor 20 which is arranged in a connection between chambers 17 and 17', which is connected to a second measuring birdge circuit 21.
  • Measuring bridge circuits 21 and 19 are each connected to a respective one of adjustable gain amplifiers 22 and 23.
  • the output signals of amplifiers 22 and 23 are subtractively combined in subtractor 24 which is connected at its output to an indicator 11.
  • the output signal of subtractor 24, which is represented in amplitude by indicator 11, is proportional to the carbon monoxide CO content in measurement gas 7.
  • the gain of amplifier 22 is advantageously adjusted so as to determine a null point of indicator 11 and the range of measurement.
  • the gain of amplifier 23 is adjusted to determine the proportion of compensation signal for the interfering components, especially for water vapor, which may vary over a large range.
  • FIG. 3 shows an infrared absorption gas analyzer which operated according to the single-beam alternating-light method with a selective receiver.
  • An infrared radiation source 1 is disposed within a reflector 2 so as to direct a beam of electromagnetic infrared energy through a measuring cell 4 which is filled with a measurement gas 3, and a receiver chamber 5.
  • Measurement gas 3 contains water vapor which is to be quantitatively determined.
  • Receiver chamber 5 contains pure sulfur hexafluoride alone or mixed with nitrogen or a rare gas. As previously noted, measuring cell 4 and receiver chamber 5 are sealed at the ends with calcium fluoride windows 6.
  • the infrared energe beam is periodically interrupted by rotating shutter 7 so as to produce alternating pressure variations which are converted into an alternating electrical signal at a resistor 11 which is connected to diaphragm capacitor 10, and a power supply flow.
  • the alternating signal is amplified and rectified by a signal processing stage 13 which produces an output signal corresponding to the water vapor content of measurement gas 3, and which is indicated by measuring instrument 14.
  • this embodiment of the invention may be incorporated into a known two-beam gas analyzer having a reference path, such as that described hereinabove with respect to FIG. 2.
  • FIG. 4 shows a gas analyzer having a non-selective receiver and subtractive filtering.
  • the infrared energy produced by infrared source 1 is directed by reflector 2 so as to propagate through measuring cell 4 and through two cells 15 and 15' which are disposed in parallel.
  • a measurement gas 3 is circulated through measurement cell 4.
  • Cell 15 may contain a gas with sulfur hexafluoride, while cell 15' contains other gas components of the measurement gas 3, or a non-absorbing gas.
  • the radiation energy which propagates through cells 15 and 15' contacts non-selective radiation receivers in the form of temperature responsive resistors 16 and 16', which are connected in a difference circuit with a power supply 17.
  • the current flowing through resistors 16 and 18 correspond to the water vapor content of measurement gas 3.
  • Resistor 18' may be advantageously adjusted to preselect the null point of an indicating instrument 14, and the ratio of the total absorptions of water vapor and sulfur hexafluoride with respect to other gas components.

Abstract

Infrared absorption gas analyzer systems are provided with cells containing sulfur hexafluoride SF6 for determining the water vapor content of the gas to be measured. In another embodiment, sulfur hexafluoride is used as a selective filter for removing spectral components from a beam of infrared energy so as to prevent cross sensitivity which interferes with the measurement of other gas components. Electrical signals proportional to the water vapor content may be produced by measuring the increase in gas pressure as infrared energy is absorbed, by use of a diaphragm capacitors. In another embodiment, temperature responsive resistors measure the relative attenuation of the infrared energy as it propagates through respective gas components.

Description

BACKGROUND OF THE INVENTION
This invention relates to systems for measuring the water vapor content of a gas mixture, and more particularly, to systems for suppressing the water vapor cross sensitivity in a non-dispersive infrared absorption gas analyzer.
Infrared absorption gas analyzers operate utilizing a physical property of gases in which the different atomic structures of different gases absorb corresponding spectral regions of infrared radiation. Such absorption of infrared energy by gas contained within a closed volume causes a measureable increase in its temperature and pressure. The concentrations of predetermined gaseous components within a gas mixture can be determined from temperature and pressure measurements.
A typical prior art system for obtaining the desired temperature and pressure measurements utilizes a source of infrared radiation which transmits electromagnetic energy in the infrared range through a measurement cell which contains a sample of the gas mixture which is to be examined, and a receiver chamber which contains a sample of the gas component, either in pure form or mixed with other gases, of the type which is desired to be measured. The measurement cell and the receiver chamber, which are each disposed in the path of the infrared energy, contain windows of a material which is transparent in the infrared spectral region, typically having wavelengths in the range between 2 and 10 microns, so as to permit the energy to propagate through the various gases.
It is a problem in the art that the gas mixture contained in the measurement cell contains gaseous components which cause "cross sensitivities". Such cross sensitivities may be caused by water vapor contained in the measurement gas, which interferes with the measurement of other gaseous components. It is desirable to eliminate the interfering component by interposing a filter cell, which is commonly filled with a filter gas corresponding to the interfering component, and which is disposed in the radiation path so as to absorb the particular interfering spectral components from the radiation. Alternatively, in the case of water vapor, it may be desirable to measure the water vapor component by filling the receiver chamber with water vapor. Thus, infrared radiation which passes through the gaseous mixture in the measurement cell would also propagate through the receiver chamber, affect the thermodynamic state of the water vapor in the receiver chamber, and such changes could be converted to electrical signals for measuring the water vapor content of the gaseous mixture in the measurement cell. The problem arises that it is difficult to contain water vapor in either a receiver chamber or in a filter cell because of its instability at ambient temperatures. Water vapor has a relatively low dew point and will tend to absorb the infrared radiation as a function of its temperature.
It is therefore an object of this invention to provide a gas which absorbs infrared energy in wavelength bands which correspond to those of water vapor, and which is chemically stable at ambient temperatures.
It is a further object of this invention to provide a stable gas which has an infrared absorption characteristic similar to that of water vapor, and which is not in general use as a gas to be measured.
It is another object of this invention to provide a gas which can be mixed with other non-absorbing filter gases such as nitrogen or argon, or with another absorbing gas, such as carbon dioxide.
SUMMARY OF THE INVENTION
The foregoing and other problems in the art are alleviated by using sulfur hexafluoride SF6 as a gas for selectively filtering spectral components corresponding to water vapor, or as a reference gas in a receiver chamber for determining the water vapor component in a gas mixture to be measured.
In some embodiments of the invention, sulfur hexafluoride can be used as a substitute for water vapor. It can be mixed with other gases in predetermined proportional quantities, so as to achieve a predeterminable partial pressure of sulfur hexafluoride in a filter gas. As indicated, such additional component gases may be of a type which do not absorb infrared radiation, such as nitrogen or argon, or may by of a type which absorb a predetermined interference component in the infrared spectrum, such as carbon dioxide. The selective filtering effect of sulfur hexafluoride may be advantageously adjustable in response to its partial pressure in the gas mixture.
A known infrared gas analyzer system which may benefit from the use of this invention is shown in German Pat. reference No. 1 109 148. In this reference, two spectrally selective radiation receivers are provided, and are disposed behind one another in the path of an infrared energy beam. The infrared radiation receivers are disposed on the other side of a measuring cell from a source of infrared radiation. The receivers are in the form of radiation-permeable, gas-filled chambers, which are provided with means for converting variation in the pressure or temperature of the gas resulting from the absorption of the infrared energy into responsive electrical output signals. The respective responsive output signals are combined in a difference circuit. In one embodiment of the invention, one of the radiation receivers is filled with sulfur hexafluoride, and the other radiation receiver is filled with the component gas to be measured. The output signal of the radiation receiver filled with sulfur hexafluoride is weighted with a percentage factor and electrically combined in the difference circuit so as to tend to counteract the output signal of the other radiation receiver. Such a differential combination of output signals compensates for water vapor cross sensitivity. Although this technique for electrically suppressing the interfering spectral component requires an increase in the cost of circuitry over known systems, such increased cost is outweighed by the advantage that the influence of water vapor as an interfering spectral component is more easily suppressed than by the careful predetermination of the partial pressure of sulfur hexafluoride in the receiver chamber, or in a filter cell.
BRIEF DESCRIPTION OF THE DRAWINGS
Comprehension of the invention is facilitated by reading the following detailed description in conjunction with the annexed drawings in which:
FIG. 1 depicts an infrared gas analyzer, partly in schematic form and partly in block and line representation, which operates in accordance with a single beam alternating light method;
FIG. 2 shows an infrared gas analyzer, partly in schematic form and partly in block and line representation, which operates in accordance with a double beam alternating light method;
FIG. 3 shows an infrared gas analyzer system, partly in schematic form and partly in block and line representation, which utilizes a single alternating beam with a selective receiver; and
FIG. 4 shows an infrared gas analyzer, partly in schematic form and partly in block and line representation, utilizing a non-selective receiver and subtractive filtering.
DETAILED DESCRIPTION
FIG. 1 shows an infrared gas analyzer which operates in accordance with the known single-beam alternating-light method. An infrared radiation source 1 is disposed within a reflector 2, so as to direct the infrared radiation along a path M. A measuring cell 3, a filter cell 4 and a receiver chamber 5 are sequentially disposed along path M. The end faces of measuring cell 3 and filter cell 4, and one end face of receiver chamber 5 are provided with windows 6 which are of an infrared transparent material, illustratively, calcium fluoride.
In operation, measurement cell 3 is filled with a measurement gas 7 which may be composed of a variety of gaseous components, including water vapor; measurement gas 7 being circulated through measuring cell 3 as shown by the directional arrows at the inlet and outlet of the measuring cell. The particular component of the measuring gas mixture 7, which is to be determined quantitatively, is present in either a pure form or mixed with non-absorbing gases as reference gas 8 in receiver chamber 5.
An increase in the pressure of the reference gas 8 resulting from the absorption of infrared radiation is transformed into a responsive electrical signal by a pressure transducer which, in this embodiment of the invention, is in the form of a diaphragm capacitor 9. Diaphragm capacitor 9 is connected to a circuit 10 which is coupled at its output to an indicating device 11. Indicating device 11 produces an indication which is responsive to the pressure of reference gas 8 in receiver chamber 5. Since diaphragm capacitor 9 and its associated circuitry will more easily process an alternating signal, the infrared energy propagating along path M is periodically interrupted by means of a rotating shutter 12.
It is a problem with this technique for measuring a component of measurement gas mixture 7 that, as a result of water vapor contained in gas mixture 7, the absorption spectrum of gas mixture 7 often overlaps the absorption spectrum of reference gas 8 in receiver chamber 5. Such spectrum overlap produces error in the output signal indicated at indicator 11, which should otherwise be proportional to only the unknown component of the measurement gas 7. In this embodiment, a filter gas 13, which is contained in filter cell 4, is used to filter out the important absorption bands of water vapor in the wavelength region between 2 and 10 microns. Filter gas 13 contains sulfur hexafluoride which may be alone, in combination with additional non-absorbing gases, or with other absorbing gases which are intended to filter out other spectral components.
FIG. 2 shows an infrared gas analyzer which operates in accordance with the two-beam alternating-light method. An infrared radiation source 1 is disposed within a reflector 2, the output beam of which is divided by beam divider 14 into two parallel ray paths, M and V. The propagation of infrared energy along paths M and V is alternatingly interrupted by rotating shutter 12. Measuring cell 3 containing a measurement gas 7, and receiver chambers 17 and 5 are disposed sequentially along path M. Reference cell 15 containing reference gas 16, and radiation receivers 17' and 5' are sequentially disposed along path V. In this embodiment, measurement gas 7 may consist of carbon monoxide, carbon dioxide and water vapor. Reference gas 16 may be a non-absorbing gas such as nitrogen N2. Receiver chambers 5 and 5' are each filled with carbon monoxide CO, which is the particular component of measurement gas 7 to be quantitatively determined. Receiver chambers 5 and 5' communicate with one another by means of a line, in which is disposed a thermal flow sensor 18. Thermal flow sensor 18 is connected to a measuring bridge circuit 19. Receiver chambers 17 and 17' are filled with a combination of sulfur hexafluoride SF6 and carbon dioxide CO2 so as to absorb the energies corresponding to the energy spectrum of interfering components carbon dioxide and water vapor H2 O of the measurement gas 7. Pressure variations are detected by thermal flow sensor 20 which is arranged in a connection between chambers 17 and 17', which is connected to a second measuring birdge circuit 21.
Measuring bridge circuits 21 and 19 are each connected to a respective one of adjustable gain amplifiers 22 and 23. The output signals of amplifiers 22 and 23 are subtractively combined in subtractor 24 which is connected at its output to an indicator 11. The output signal of subtractor 24, which is represented in amplitude by indicator 11, is proportional to the carbon monoxide CO content in measurement gas 7. The gain of amplifier 22 is advantageously adjusted so as to determine a null point of indicator 11 and the range of measurement. The gain of amplifier 23 is adjusted to determine the proportion of compensation signal for the interfering components, especially for water vapor, which may vary over a large range.
FIG. 3 shows an infrared absorption gas analyzer which operated according to the single-beam alternating-light method with a selective receiver. An infrared radiation source 1 is disposed within a reflector 2 so as to direct a beam of electromagnetic infrared energy through a measuring cell 4 which is filled with a measurement gas 3, and a receiver chamber 5. Measurement gas 3 contains water vapor which is to be quantitatively determined. Receiver chamber 5 contains pure sulfur hexafluoride alone or mixed with nitrogen or a rare gas. As previously noted, measuring cell 4 and receiver chamber 5 are sealed at the ends with calcium fluoride windows 6.
Selected spectral portions of the infrared energy which enters receiver chamber 5 are absorbed by gas 8 which increases in temperature and pressure, so as to deflect diaphragm 9 of diaphragm capacitor 10. As indicated, the infrared energe beam is periodically interrupted by rotating shutter 7 so as to produce alternating pressure variations which are converted into an alternating electrical signal at a resistor 11 which is connected to diaphragm capacitor 10, and a power supply flow. The alternating signal is amplified and rectified by a signal processing stage 13 which produces an output signal corresponding to the water vapor content of measurement gas 3, and which is indicated by measuring instrument 14. In similar manner, this embodiment of the invention may be incorporated into a known two-beam gas analyzer having a reference path, such as that described hereinabove with respect to FIG. 2.
FIG. 4 shows a gas analyzer having a non-selective receiver and subtractive filtering. The infrared energy produced by infrared source 1 is directed by reflector 2 so as to propagate through measuring cell 4 and through two cells 15 and 15' which are disposed in parallel. A measurement gas 3 is circulated through measurement cell 4. Cell 15 may contain a gas with sulfur hexafluoride, while cell 15' contains other gas components of the measurement gas 3, or a non-absorbing gas.
The radiation energy which propagates through cells 15 and 15' contacts non-selective radiation receivers in the form of temperature responsive resistors 16 and 16', which are connected in a difference circuit with a power supply 17. The current flowing through resistors 16 and 18 correspond to the water vapor content of measurement gas 3. Resistor 18' may be advantageously adjusted to preselect the null point of an indicating instrument 14, and the ratio of the total absorptions of water vapor and sulfur hexafluoride with respect to other gas components.
Although the inventive concept disclosed herein has been described in terms of specific embodiments and applications, other applications and embodiments will be obvious to persons skilled in the pertinent art without departing from the scope of the invention. The drawings and descriptions of specific embodiments of the invention in this disclosure are illustrative of applications of the invention and should not be construed to limit the scope thereof.

Claims (8)

I claim:
1. A non-dispersive infrared gas analyzer for detecting a predetermined component of a first gas mixture which is free of sulfur hexafluoride, one such component gas the gas analyzer being of the type which contains a source of infrared radiation for producing a beam of infrared radiation and a measurement cell for holdng the first gas mixture in the path of the beam of infrared radiation;
CHARACTERIZED IN THAT there are further provided
(a) a first chamber disposed in the path of the beam of infrared radiation containing a second gas containing sulfur hexafluoride, said sulfur hexafluoride having an infrared energy absorption characteristic corresponding to that of water vapor, so as to absorb energy from said beam of infrared radiation in preselected spectral energy bands; and
(b) detector means responsive to said beam of infrared radiation for producing an electric signal responsive to variations in the beam of infrared radiation.
2. The non-dispersive infrared gas analyzer of claim 1 wherein there is further provided
(a) a second chamber disposed in the path of the beam of infrared radiation, said first chamber being interposed between said second chamber and the source of infrared radiation, for holding a third gas containing a preselected component gas of the first gas mixture.
3. The non-dispersive infrared gas analyzer of claim 2 wherein said detector means comprises a diaphragm capacitor having a diaphragm for moving in response to variations in the pressure of said third gas in said second chamber.
4. The non-dispersive infrared gas analyzer of claim 1 wherein said detector means comprises a diaphragm capacitor having a diaphragm for moving in response to variations in the pressure of said second gas in said first chamber.
5. The non-dispersive infrared gas analyzer of claim 1 wherein there is further provided
(a) a third chamber disposed in the path of the beam of infrared radiation, and in parallel with said first chamber, with respect to the beam of infrared radiation, for holding a fourth gas, said fourth gas having a predetermined infrared energy absorption characteristic.
6. The non-dispersive infrared gas analyzer of claim 5 wherein said detector means comprises
(a) first sensor means for producing an electrically measureable condition responsive to a first portion of said beam of infrared radiation which propagates through said first chamber,
(b) second sensor means for producing an electrically measureable condition responsive to a second portion of said beam of infrared radiation which propagates the said third chamber, and
(c) difference circuit means for producing a difference signal responsive to the difference between the respective electrically measureable conditions produced by said first and second sensor means.
7. A non-dispersive infrared gas analyzer for detecting a predetermined component of a first gas mixture which is free of sulfur hexafluoride, the gas analyzer being of the type which contains a source of infrared radiation for producing a beam of infrared energy, and a cell for holding the first gas mixture in the path of the beam of infrared energy;
CHARACTERIZED IN THAT there are further provided
(a) a first chamber containing a second gas containing sulfur hexafluoride in the path of the beam of infrared energy;
(b) a second chamber for holding a third gas containing a predetermined component gas of the first gas mixture in the path of the beam of infrared energy; and
(c) detector means in said first chamber responsive to variations in selected thermodynamic parameters in said second gas, the variations being responsive to the infrared energy which is absorbed.
8. A non-dispersive infrared gas analyzer for detecting a predetermined component of a first gas mixture which is free of sulfur hexafluoride, the gas analyzer being of the type which contains a source of infrared radiation for producing a beam of infrared energy, and a cell for holding the first gas mixture in the path of the beam of infrared energy;
CHARACTERIZED IN THAT there are provided
(a) a first chamber containing a second gas containing sulfur hexafluoride in the path of the beam of infrared energy;
(b) a second chamber for holding a third gas containing a predetermined component gas of the first gas mixture in the path of the beam of infrared energy; and
(c) detector means in said second chamber responsive to variations in selected thermodynamic parameters in said third gas, the variations being responsive to the infrared energy which is absorbed.
US06/014,432 1978-02-24 1979-02-23 Non-dispersive infrared gas analyzer for testing gases containing water-vapor Expired - Lifetime US4271124A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19782808033 DE2808033A1 (en) 1978-02-24 1978-02-24 DEVICE FOR SUPPRESSION OF WATER VAPOR CROSS-SENSITIVITY IN A NON-DISPERSIVE INFRARED GAS ANALYZER
DE2808033 1978-02-24

Publications (1)

Publication Number Publication Date
US4271124A true US4271124A (en) 1981-06-02

Family

ID=6032870

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/014,432 Expired - Lifetime US4271124A (en) 1978-02-24 1979-02-23 Non-dispersive infrared gas analyzer for testing gases containing water-vapor

Country Status (5)

Country Link
US (1) US4271124A (en)
JP (1) JPS54121198A (en)
DE (1) DE2808033A1 (en)
FR (1) FR2418460A1 (en)
GB (1) GB2015154B (en)

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4413427A (en) * 1981-07-29 1983-11-08 Aer Corporation Fuel control system for dryer
US4525328A (en) * 1982-03-05 1985-06-25 Leco Corporation Carbon, hydrogen, and nitrogen analyzer
US4573910A (en) * 1982-03-05 1986-03-04 Leco Corporation Carbon, hydrogen, and nitrogen analyzer
US4605313A (en) * 1985-04-10 1986-08-12 Environmental Research & Technology, Inc. Infrared detector for NDIR gas analysis
US4622009A (en) * 1982-03-05 1986-11-11 Leco Corporation Carbon, hydrogen, and nitrogen analyzer
US4692622A (en) * 1984-12-04 1987-09-08 Fuji Electric Co., Ltd. Infrared analyzer
US4794255A (en) * 1985-11-27 1988-12-27 Horiba, Ltd. Absorption analyzer
US4839767A (en) * 1987-02-02 1989-06-13 Mitsubishi Denki Kabushiki Kaisha Element and device for detecting internal faults in an insulating gas charged electrical apparatus
US5124859A (en) * 1991-05-24 1992-06-23 Gte Government Systems Corporation Narrow bandpass reflective optical filter
US5130544A (en) * 1987-09-15 1992-07-14 Gambro Engstrom Ab Optical gas analyzer
US5132231A (en) * 1991-05-16 1992-07-21 Case Western Reserve University Carbon monoxide detector using a derivative of Ni(TBC)
US5271900A (en) * 1990-03-09 1993-12-21 Shimadzu Corporation Carbon analyzer for both aqueous solutions and solid samples
US5279146A (en) * 1991-08-17 1994-01-18 Horiba Ltd. Method and apparatus for real time measurement of particulate matter in combustion gases
US5340542A (en) * 1991-05-10 1994-08-23 Hartmann & Braun Aktiengesellschaft Apparatus for the measurement of the total content of organic carbon and nitrogen in water
US5429805A (en) * 1993-01-08 1995-07-04 Fuji Electric Co., Ltd. Non-dispersive infrared gas analyzer including gas-filled radiation source
US5459075A (en) * 1992-09-22 1995-10-17 Hartmann & Braun Ag Apparatus for measuring the total content of organic carbon and nitrogen in water
EP0740146A2 (en) * 1995-04-04 1996-10-30 HEKATRON GmbH Device for detecting a gas or aerosol
US5572032A (en) * 1993-11-20 1996-11-05 Horiba, Ltd. Gas analyzer and gas-analyzing mechanism
US20050173635A1 (en) * 2004-02-09 2005-08-11 Smith Patrick G. Gas detector
US20060118724A1 (en) * 2004-10-26 2006-06-08 Tomoaki Nanko Infrared gas analyzer and infrared gas analysis method
US20080277586A1 (en) * 2007-05-07 2008-11-13 Dennis Cardinale Low-Power Fast Infrared Gas Sensor, Hand Held Gas Leak Detector, and Gas Monitor Utilizing Absorptive-Photo-Acoustic Detection
US20090187111A1 (en) * 2007-03-08 2009-07-23 Fsp Instruments, Inc. Gas analyzer
US20100116027A1 (en) * 2007-02-21 2010-05-13 Teledyne Tekmar Company Pressurized detectors substance analyzer
US8143580B1 (en) * 2009-04-14 2012-03-27 Jacob Y Wong Crossed biased filtering NDIR gas sensing methodology
US20130208280A1 (en) * 2010-06-25 2013-08-15 Siemens Aktiengesellschaft Non-Dispersive Gas Analyzer
EP3772644A1 (en) * 2019-08-06 2021-02-10 Siemens Aktiengesellschaft Non-dispersive infrared gas analyzer for determining at least two gas components in a measuring gas
CN113155771A (en) * 2021-03-24 2021-07-23 华中农业大学 Split type quick accurate blade water potential survey device
US20220307975A1 (en) * 2021-03-25 2022-09-29 Asahi Kasei Microdevices Corporation Gas sensor

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5047352A (en) * 1985-05-20 1991-09-10 Arch Development Corporation Selective chemical detection by energy modulation of sensors
GB2175399B (en) * 1985-05-20 1989-10-11 Us Energy Selective chemical detection by energy modulation of sensors
DE3815184A1 (en) * 1988-05-04 1989-11-16 Siemens Ag PNEUMATIC DETECTOR FOR NDIR ANALYZER
DE8905226U1 (en) * 1989-04-25 1990-06-13 Siemens Ag, 1000 Berlin Und 8000 Muenchen, De
DE9006169U1 (en) * 1990-05-31 1991-07-18 Siemens Ag, 1000 Berlin Und 8000 Muenchen, De
DE4432940C2 (en) * 1993-09-24 1997-10-02 Fuji Electric Co Ltd Infrared gas analyzer
DE19739255A1 (en) * 1997-08-18 1999-03-04 Hartmann & Braun Gmbh & Co Kg Nitrous oxide measurements
DE19957364B4 (en) * 1998-11-30 2006-09-14 Ust Umweltsensortechnik Gmbh Method and device for determining the concentration of gases
GB2358245A (en) * 1999-10-21 2001-07-18 Pittway Corp Photo-acoustic gas sensor
DE102004055741B4 (en) * 2004-11-18 2007-03-15 Siemens Ag Non-dispersive infrared gas analyzer according to the two-jet principle
CN109297958B (en) * 2018-11-13 2021-08-17 国网四川省电力公司成都供电公司 Be used for real time monitoring SF6 power equipment insulating gas decomposition product colour development early warning device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3021427A (en) * 1958-06-02 1962-02-13 Ca Atomic Energy Ltd Light water analyser
US3725702A (en) * 1969-01-29 1973-04-03 Hartmann & Braun Ag Infrared gas analyzer
US3925667A (en) * 1973-10-20 1975-12-09 Hartmann & Braun Ag Two beam infrared gas analyzer
US4065207A (en) * 1976-09-17 1977-12-27 The United States Of America As Represented By The Secretary Of The Army Programmable power attenuator for continuous CO2 lasers

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2924713A (en) * 1956-01-18 1960-02-09 Beckman Instruments Inc Instruments
DE2039538A1 (en) * 1970-08-08 1972-02-17 Hartmann & Braun Ag Ethylene oxide conc measurement - using infrared gas analyser
DE2803369C2 (en) * 1978-01-26 1982-03-04 Siemens AG, 1000 Berlin und 8000 München Measuring device for determining the proportion of water vapor in a gas mixture by means of infrared absorption gas analysis

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3021427A (en) * 1958-06-02 1962-02-13 Ca Atomic Energy Ltd Light water analyser
US3725702A (en) * 1969-01-29 1973-04-03 Hartmann & Braun Ag Infrared gas analyzer
US3925667A (en) * 1973-10-20 1975-12-09 Hartmann & Braun Ag Two beam infrared gas analyzer
US4065207A (en) * 1976-09-17 1977-12-27 The United States Of America As Represented By The Secretary Of The Army Programmable power attenuator for continuous CO2 lasers

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4413427A (en) * 1981-07-29 1983-11-08 Aer Corporation Fuel control system for dryer
US4525328A (en) * 1982-03-05 1985-06-25 Leco Corporation Carbon, hydrogen, and nitrogen analyzer
US4573910A (en) * 1982-03-05 1986-03-04 Leco Corporation Carbon, hydrogen, and nitrogen analyzer
US4622009A (en) * 1982-03-05 1986-11-11 Leco Corporation Carbon, hydrogen, and nitrogen analyzer
US4692622A (en) * 1984-12-04 1987-09-08 Fuji Electric Co., Ltd. Infrared analyzer
US4605313A (en) * 1985-04-10 1986-08-12 Environmental Research & Technology, Inc. Infrared detector for NDIR gas analysis
US4794255A (en) * 1985-11-27 1988-12-27 Horiba, Ltd. Absorption analyzer
US4839767A (en) * 1987-02-02 1989-06-13 Mitsubishi Denki Kabushiki Kaisha Element and device for detecting internal faults in an insulating gas charged electrical apparatus
US5130544A (en) * 1987-09-15 1992-07-14 Gambro Engstrom Ab Optical gas analyzer
US5271900A (en) * 1990-03-09 1993-12-21 Shimadzu Corporation Carbon analyzer for both aqueous solutions and solid samples
US5340542A (en) * 1991-05-10 1994-08-23 Hartmann & Braun Aktiengesellschaft Apparatus for the measurement of the total content of organic carbon and nitrogen in water
US5132231A (en) * 1991-05-16 1992-07-21 Case Western Reserve University Carbon monoxide detector using a derivative of Ni(TBC)
US5124859A (en) * 1991-05-24 1992-06-23 Gte Government Systems Corporation Narrow bandpass reflective optical filter
US5279146A (en) * 1991-08-17 1994-01-18 Horiba Ltd. Method and apparatus for real time measurement of particulate matter in combustion gases
US5459075A (en) * 1992-09-22 1995-10-17 Hartmann & Braun Ag Apparatus for measuring the total content of organic carbon and nitrogen in water
US5429805A (en) * 1993-01-08 1995-07-04 Fuji Electric Co., Ltd. Non-dispersive infrared gas analyzer including gas-filled radiation source
US5572032A (en) * 1993-11-20 1996-11-05 Horiba, Ltd. Gas analyzer and gas-analyzing mechanism
EP0740146A2 (en) * 1995-04-04 1996-10-30 HEKATRON GmbH Device for detecting a gas or aerosol
EP0740146B1 (en) * 1995-04-04 2004-10-06 HEKATRON GmbH Device for detecting a gas or aerosol
US20050173635A1 (en) * 2004-02-09 2005-08-11 Smith Patrick G. Gas detector
US20060118724A1 (en) * 2004-10-26 2006-06-08 Tomoaki Nanko Infrared gas analyzer and infrared gas analysis method
US7323687B2 (en) * 2004-10-26 2008-01-29 Yokogawa Electric Corporation infrared gas analyzer and infrared gas analysis method
US8128874B2 (en) * 2007-02-21 2012-03-06 Teledyne Instruments, Inc. Pressurized detectors substance analyzer
US20100116027A1 (en) * 2007-02-21 2010-05-13 Teledyne Tekmar Company Pressurized detectors substance analyzer
US20090187111A1 (en) * 2007-03-08 2009-07-23 Fsp Instruments, Inc. Gas analyzer
US20110001625A1 (en) * 2007-03-08 2011-01-06 Fsp Instruments, Llc. Gas analyzer
US20080277586A1 (en) * 2007-05-07 2008-11-13 Dennis Cardinale Low-Power Fast Infrared Gas Sensor, Hand Held Gas Leak Detector, and Gas Monitor Utilizing Absorptive-Photo-Acoustic Detection
US8143580B1 (en) * 2009-04-14 2012-03-27 Jacob Y Wong Crossed biased filtering NDIR gas sensing methodology
US20130208280A1 (en) * 2010-06-25 2013-08-15 Siemens Aktiengesellschaft Non-Dispersive Gas Analyzer
US9030666B2 (en) * 2010-06-25 2015-05-12 Siemens Aktiengeselschaft Non-dispersive gas analyzer
EP3772644A1 (en) * 2019-08-06 2021-02-10 Siemens Aktiengesellschaft Non-dispersive infrared gas analyzer for determining at least two gas components in a measuring gas
CN113155771A (en) * 2021-03-24 2021-07-23 华中农业大学 Split type quick accurate blade water potential survey device
US20220307975A1 (en) * 2021-03-25 2022-09-29 Asahi Kasei Microdevices Corporation Gas sensor
US11835451B2 (en) * 2021-03-25 2023-12-05 Asahi Kasei Microdevices Corporation Gas sensor

Also Published As

Publication number Publication date
FR2418460A1 (en) 1979-09-21
JPS54121198A (en) 1979-09-20
GB2015154A (en) 1979-09-05
JPS616334B2 (en) 1986-02-25
DE2808033A1 (en) 1979-08-30
GB2015154B (en) 1982-07-21
FR2418460B1 (en) 1984-01-06

Similar Documents

Publication Publication Date Title
US4271124A (en) Non-dispersive infrared gas analyzer for testing gases containing water-vapor
US5464983A (en) Method and apparatus for determining the concentration of a gas
US4204768A (en) Gas analysers of the selective radiation absorption type with a calibration cell
US2924713A (en) Instruments
US3869613A (en) Infrared gas analyzers
US4236827A (en) Opto-acoustic gas analyzer
US3162761A (en) Apparatus for analyzing a mixture of substances by selective absorption of infrared radiation
US4176963A (en) Device for determining the nitrogen oxide concentration in a gaseous mixture
JPH03503446A (en) Dual sample cell gas analyzer
US5585635A (en) Infrared gas analyzer and method
US4355233A (en) Method and apparatus for negating measurement effects of interferent gases in non-dispersive infrared analyzers
US5559333A (en) Apparatus of non-dispersive infrared analyzer
US3976883A (en) Infrared analyzer
CA1140772A (en) Absorption cell gas monitor
US3171027A (en) Infrared atmospheric contamination detector system with the detector interrupted at a sub-harmonic frequency of the source
US4027972A (en) Gas analyzer method and apparatus
US4803052A (en) Carbon monoxide detector
US3091690A (en) Two path infrared gas analyzer having one enclosed path
JPS6217183B2 (en)
JPH03221843A (en) Analyzer by light
US4468561A (en) Nondispersive infrared gas analyzer
US3970387A (en) Nondispersion, two beam, infrared gas analyzer
US3922551A (en) Detection of CO{HD 2 {B in a hyperbaric gaseous environment
US3193676A (en) Infra-red gas analysers
JPH08247942A (en) Infrared ray gas analyzer